The present invention relates to a method of producing precipitated calcium carbonate using fowl egg shells. More particularly, the method comprises a heat treatment step, a grinding step, a dry-quenching step, a carbonizing step, and a filtering and drying step.
During the past several decades, there has been an industrial demand for calcareous products that continues to expand. Such calcareous products are largely classified into ground calcium carbonate directly obtained by grinding limestone and precipitated calcium carbonate prepared by a chemical method.
In contrast to the ground calcium carbonate that is uneven in the shape of particles, the precipitated calcium carbonate are composed of extremely small particles uniform in shape and thus considered as a high value-added material useful in the fields of household items, such as paints, toothpaste, or stationery, foods, and medical substances, as well as in the field of fine synthetic chemistry, such as paper, plastic, rubber, etc.
The development of mineral resources such as calcium carbonate has recently encountered some difficulties due to high cost for development and a rising attention to environmental preservation. Particularly, the conventional precipitated calcium carbonate is prepared primarily through synthesis of materials in the form of limestone. Limestone, however, varies a lot in quality according to the place of production, which leads to the need of performing additional pretreatment and synthesis processes and thus increases the production cost.
Moreover, limestone has a large grain size number and a dense structure and thus exhibits low thermal dissociation rate. Heat transfer is poor through pores in the coarse limestone, and carbon dioxide generated from thermal dissociation has the difficulty in escaping from the dense structure of limestone through the dense structure of limestone. Thus, the partial pressure of carbon dioxide increases relatively on the interface where thermal dissociation occurs, making the thermal dissociation rate lower. This causes the need for heat treatment at high temperature and hence leads to an increase in the production cost.
Further, the precipitated calcium carbonate prepared using limestone contains a large amount of impurities. And, carbon dioxide generated during the pretreatment process for limestone causes environmental contamination.